- range selector
- receiving element
- recording balance
- recording hygrometer
- recording pyrometer
- rebalance
- receiving gage
- receiving gauge
- record-player
- recording chart
- rectifier instrument
- reducing flowmeter
- reference
- reference standards
- reference temperature
- referenced ramp
- refrigerant flowmeter
- regeneration
- regenerative feedback
- register ton
- redwood viscometer
- reference measurement
- register control
- regulated
- regulator
- remote indication
- reference conditions
- register tonnage
- regulating action
- repeatable measurement
- repeating accuracy
- regulation
- relative sensitivity
- replica master
- reset action
- reset counter
- residual mode
- resistance gauge
- resistive bridge
- resolution
- response characteristic
- response time
- resistance gage
- rigid network
- reversible counter
- rise time
- return difference
- ring balance
- ringing
- reversed scale
- revisit rate
- rod thermometer
- Roman steelyard
- room calorimeter
- rood
- roof tube
- safety disc
- ruler
- sacking balance
- safe yield
- rotational viscometer
- ruddle
- sample stream
- sampler
- sampling action
- sampling control
- sampling controller
- sampling cycle
- sampling element
- sampling hole
- sampling oscilloscope
- satellite telemetry
- scale spacing
- satisfactory
- scope monitor
- screw pitch
- scale numbering
- scattered data
- Scott viscometer
- Saybolt viscometer
- scale length
- scale mark
- science laboratory
- screw gauge
- scriber
- seepage pipe
- seepage tube
- self-balance
- seismologist
- seismic disturbance
- sensitometer
- separation theorem
- sepatrix
- sensible heat
- service gauge
- servo positioner
- servomotor
- set point
- servo controller
- servocontrol